Copolymeric latexes made water-redispersible by presence of six-membered carbocyclic compound having two vicinal carboxyl substituents

ABSTRACT

LATEX COMPOSITIONS, WHICH AFTER BEING DRIED ARE REDISPERSIBLE IN WATER, COMPRISE AQUEOUS DISPERSIONS OF FILMFORMING CARBOXYL-CONTAINING POLYMERS AND A SIX-MEMBERED CARBOXYLIC COMPOUND HAVING TWO VICINAL CARBOXYL SUBSTITUENTS AND WHICH IS SOLUBLE IN AQUEOUS ALKALINE MEDIA. THE DRIED COMPOSITIONS AFTER BEING REDISPERSED IN WATER PROVIDE RECONSTITUTED LATEXES WHICH HAVE APPROXIMATELY THE SAME PARTICLE SIZE AS THE ORIGINAL LATEX. REPRESENTATIVE COMPOSITIONS ARE BLEND OF THE DISODIUM SALT OF 1,2,3,6-TETRAHYDROPHTHALIC ACID AND A LATEX OF A COPOLYMER OF STYRENE, BUTADIENE AND ACRYLIC ACID AS WELL AS DRIED FILMS OR DRIED POWDERS OBTAINED THEREFROM. THE COMPOSITIONS ARE OBTAINED BY MIXING THE CARBOCYLIC COMPOUND WITH THE LATEX CONSTITUENTS EITHER BEFORE, DURING OR AFTER PREPARATION OF THE LATEX OR ARE OBTAINEED BY IN SITU FORMATION OF THE CARBOCYCLIC COMPOUND DURING EMULSION POLYMERIZATION.

United States Patent O COPOLYMERIC LATEXES MADE WATER-REDIS- PERSIBLE BYPRESENCE OF SIX-MEMBERED CARBOCYCLIC COMPOUND HAVING TWO VICI- NALCARBOXYL SUBSTITUENTS Alfred R. Nelson, Bay City, Mich., assignor to TheDow Chemical Company, Midland, Mich.

No Drawing. Continuation-impart of application Ser. No. 234,319, Mar.13, 1972. This application Jan. 22, 1973, Ser. No. 325,250

Int. Cl. C08f 15/40 US. Cl. 260-2943 H 20 Claims ABSTRACT OF THEDISCLOSURE Latex compositions, which after being dried are redispersiblein water, comprise aqueous dispersions of filmformingcarboxyl-containing polymers and a six-membered carbocyclic compoundhaving two vicinal carboxyl substituents and which is soluble in aqueousalkaline media. The dried compositions after being redispersed in waterprovide reconstituted latexes which have approximately the same particlesize as the original latex. Representative compositions are a blend ofthe disodium salt of 1,2,3,6-tetrahydrophthalic acid and a latex of acopolymer of styrene, butadiene and acrylic acid as well as dried filmsor dried powders obtained therefrom. The compositions are obtained bmixing the carbocyclic com pound with the latex constituents eitherbefore, during or after preparation of the latex or are obtained by insitu formation of the carbocyclic compound during emulsionpolymerization.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is acontinuation-in-part of application Ser. No. 234,319 filed Mar. 13,1972, now abandoned.

BACKGROUND OF THE INVENTION (1) Field of the Invention The presentinvention is concerned with latexes of filmforming polymers which whendried are redispersible in water to yield latex compositions havingapproximately the same particle size as the original latex compositionand is concerned with films and powders obtained from such latexes.

(2) Description of the Prior Art Because of the potential for saving inshipping costs, there has been interest for some time in latex polymersystems which contain a minimum amount of water. United States Pat. No.3,232,899, which issued to Leonard F. Guziak, Feb. 1, 1966, describes areconstitutable latex of a polymer which contains from 15 to 40 parts ofan interpolymerized ethylenically unsaturated acid, preferably acrylicacid or methacrylic acid. The polymers described, however, are not filmforming. While a coalescing agent ma be added to the reconstituted latexof that patent to provide film-formation, the patent discloses that bysuch treatment the polymer has lost any tendency to be reconstituted.

In United States Pat. No. 3,409,578, issued Nov. 5, 1968, to Jesse C. H.Hwa, there is disclosed the preparation of dry, particulate,water-insoluble, film-forming or non-film-forming polymers adapted to bedispersed directly in water by adding to a latex, which must containcarboxylate groups, a surface-hardening metal ion to form a skin aroundthe polymer particles which prevents fusion of the particles together ondrying. In order to redisperse the polymer particles to produce a latexhaving 3,822,230 Patented July 2, 1974 SUMMARY OF THE INVENTION Thepresent invention provides a latex composition having an averageparticle diameter from about 500 Augstroms to about 10,000 Angstroms,preferably from about 1500 Angstroms to about 4,000 Angstroms, which canbe deposited as a film and dried or can be spray dried to form a powderyproduct and such dried films or powders are dispersible in water to forma reconstituted latex having approximatel the same particle size as theoriginal latex.

The latex composition comprises an aqueous colloidal dispersion of afilm-forming copolymer of from about 1 percent to about 10 percent,preferably from about 3 percent to about 5 percent, of ana,;3-ethylenically unsaturated carboxylic acid and the balance of anessentially water-insoluble, ethylenically unsaturated monomericcomposition and a six-membered carbocyclic compound having two vicinalcarboxyl substituents which is soluble in aqueous alkaline media, in anamount effective to provide water-redispersibility of the copolymerresidue obtained by drying the latex. The latex compositions may beobtained by the additive method, i.e., b mixing the six-membered-ringcarbocyclic compound with film forming latexes having a polymericcomponent containing the required amount of copolymerized ethylenicallyunsaturated carboxylic acid or they may be obtained by the in situmethod wherein certain of the carbocyclic compounds can be formed insitu during emulsion polymerization of monomeric compositions (whichmust include an ali phatic conjugated diene) to prepare the latex. Inthe in situ preparation, from about 2.5 percent to about 13 percent,preferably from about 4 percent to about 8 percent, of fumaric acid orof a monomethyl, monoethyl or mono propyl ester of an a,fl-ethylenicallyunsaturated dicarboxylic acid, from about 20 percent to 97.5 percent,prefer ably from about 30 percent to about percent, and especiallygreater than about 35 percent of an aliphatic conjugated diene and thebalance of another copolymerizable, neutral, ethylenically unsaturatedmonomer are subjected to emulsion polymerization conditions at an acidpH.

To form a redispersible dry product, sufiicient watersoluble base-actingcompound is added to the latex product to provide a pH of from about 7to about 14, pref erably from about 8 to about 12, then the resultingprod net is dried such as by freeze-drying, by spray-drying, or bycasting a wet film and allowing that film to dry at ambient temperatureor at a temperature below about C., preferably below about 60 C.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compositions of the presentinvention contain a mixture of a film-forming copolymer and asix-membered carbocyclic compound having two vicinal carboxylsubstituents which is soluble in aqueous alkaline media and are preparedeither by the addition of such a soluble carbocyclic compound to apreformed latex or by the in situ preparation of the carbocycliccompound and the copolymer comprising the latex by an emulsionpolymerization process. For brevity, the methods are sometimes referredto hereinafter as the additive method when the carbocyclic compound perse is added either before, during, or after polymerizing the monomericcomponents of the latex and as the in situ method" when the carbocycliccompound is formed during emulsion polymeriza:

atoms, are phthalic acid (ortho-phthalic acid) and modified phthalicacid compounds which are soluble in aqueous alkaline media, i.e., in anaqueous solution containing sufficient water-soluble base to maintain apH greater than 7 and less than about 14. The term six-membered refersonly to the number of carbon atoms in the carbocyclic ring. By the Wordmodified" in the term modidied phthalic acid compounds is meantsubstitution of other substituents such as alkyl or halogen forhydrogens on ring-carbon atoms and/ or different degrees of doublebondunsaturation of the carbocyclic ring; for example, phthalic acid per seis completely unsaturated, hexahydrophthalic acid is completelysaturated whereas 1,2,3,6-

- tetrahydrophthalic acid and 1,3-cyclohexadiene-1,2-dicarboxylic acidhave an intermediate degree of saturation. The six-membered carbocycliccompounds having two .vicinal carboxyl substituents which are soluble inaqueous alkaline media are represented by phthalic acid,

S-methylphthalic acid,

4-methylphthalic acid,

4-methoxyphthalic acid,

3,4-dimethylphthalic acid,

3,4-dimethoxyphthalic acid, 3,4-dimethoxy-6-nitrophthalic acid,4-methoxy-3,6-dimethylphthalic acid, 4,5-dimethoxyphthalic acid,

4,5-diethoxyphthalic acid, 4-chloro-5-methoxyphthalic acid,3,6-difiuorophthalic acid,

tetrachlorophthalic acid,

tetrabromophthalic acid, 3-bromo-4-ethoxy-S-methoxyphthalic acid,B-phenylphthalic acid,

4-benzylphthalic acid, 1,3-cyclohexadiene-1,2-dicarboxylic acid,1,4-cyclohexadiene-1,2-dicarboxylic acid,3-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid,3-methyl-4,6-cyclohexadiene-1,2-dicarboxylic acid,3-methyl-3,6-cyclohexadiene-1,2-dicarboxylic acid,4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid,S-methyl-2,4-cyclohexadiene-1,2-dicarboxylic acid,3,4-dimethyl-1,4-cyclohexadiene-1,2-dicarboxylic acid,3,4-dimethyl-4,6-cyclohexadiene-1,2-dicarboxylic acid,1,2,3,6-tetrahydrophthalic acid, and hexahydrophthalic acid.

In the additive method of preparation wherein the carbocyclic compound,as heretofore defined, is mixed with a pre-formed latex, there are manyknown latexes which are suitable in the practice of the invention. It isrequired that such latexes contain a copolymer of from about 1 percentto about 10 percent of an edit-ethylenically unsaturated carboxylic acidand a substantially water-soluble ethylenically unsaturated monomericcomposition wherein the copolymer is film-forming at temperatures belowabout 95 C., preferably below about 30 C., and has a particle sizewithin the range of from about 500 Angstroms to about 10,000 Angstroms.

The a,fi-ethylenically unsaturated carboxylic acids may bemonocarboxylic or polycarboxylic and ordinarily have from 3 to 6 carbonatoms although acids having a greater number of carbon atoms such as upto 10 may be used. Representative of the unsaturated monocarboxylicacids are acrylic acid, methacrylic acid, ethacrylic acid, crotonicacid, sorbic acid, hydrosorbic acid and cinnamic acid. Representative ofunsaturated polycarboxylic acids are maleic acid, fumaric acid, itaconicacid, citraconic acid, mesaconic acid and aconitic acid.

The ethylenically unsaturated monomeric composition which iscopolymerized with such unsaturated acids in the pre-formed latexesincludes one or more monoethylenically unsaturated, copolymerizablemonomers which form hydrophobic polymers and/or an aliphatic conjugateddiene.

The copolymerizable, ethylenically unsaturated compounds which ashomopolymers or as copolymers with each other are hydrophobic arerepresented by, but not restricted to, non-ionic monoethylenicallyunsaturated monomers such as the alkenyl aromatic compounds, i.e., thestyrene compounds, the derivatives of tit-methylene monocarboxylic acidssuch as the acrylic esters, acrylic nitriles and methacrylic esters;derivatives of a,B-ethylenically unsaturated dicarboxylic acids such asmaleic diesters; unsaturated alcohol esters; unsaturated ketones;unsaturated ethers; and other polymerizable vinylidene compounds such asvinyl chloride and vinylidene chloride. Specific examples of suchethylenically unsaturated compounds are styrene, a-methylstyrene,ar-methylstyrene, ar-ethylstyrene, a,ar-dimethylstyrene,ar,ar-dimethylstyrene, ar,ar-diethylstyrene, t-butylstyrene,vinylnaphthalene, hydroxystyrene, methoxystyrene, cyanostyrene,acetylstyrene, monochlorostyrene, dichlorostyrene, and otherhalostyrenes, methyl methacrylate, ethyl acrylate, butyl acrylate, hexylacrylate, 2-ethylhexyl acrylate, lauryl methacrylate, phenyl acrylate,2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutylacrylate, and 4-hydroxybutyl methacrylate; acrylonitrile,methacrylonitrile, acryloanilide, ethyl ot-chloroacrylate, diethylmaleate, dimethyl fumarate, diethyl itaconate, vinyl acetate, vinylpropionate, vinyl chloride, vinyl bromide, vinylidene chloride,vinylidene fluoride, vinyl mflelthyl ketone, methyl isopropenyl ketone,and vinyl ethyl e er.

By the term aliphatic conjugated diene it is meant to include,typically, 1,3-butadiene, 2-methyl-1,3-butadiene,2,3-dimethyl-1,3-butadiene, piperylene, 2-neopentyl-l,3- butadiene, andother hydrocarbon homologs of 1,3-butadiene, and, in addition, thesubstituted dienes, such as 2- chloro-l,3-butadiene,2-cyano-1,3-butadiene, the substituted straight-chain conjugatedpentadienes, the straight and branched-chain hexadienes, and the like.Usually the conjugated dienes have from 4 to 10 carbon atoms. The1,3-butadiene hydrocarbons, and 1,3-butadiene and isoprene specifically,because of their ability to produce particularly desirable polymericmaterial, are preferred. The aqueous dispersions used in the practice ofthis invention are conveniently prepared from the above-describedmonomers by conventional emulsion polymerization at acid pH using smallamounts of conventional emulsifiers and free-radical producing catalystsusually in an amount from about 0.01 percent to about 3 percent based'on the weight of the monomers under conventional conditions ofagitation, time, pressure, and temperature, using either a batchwise,incremental or continuous type addition of the monomers, water and otherconstituents to a reaction vessel or to a series of such vessels or bypolymerization in a coil reactor.

The catalysts are of the type which produce free radicals andconveniently are per-oxygen compounds; for example, the inorganicpersulfate compounds such as sodium persulfate, potassium persulfate andammonium persulfate; the inorganic peroxides such as hydrogen peroxide;the organic hydroperoxides such as cumene hydroperoxide and t-butylhydroperoxide; the organic peroxides such as benzoyl peroxide, acetylperoxide, lauroyl peroxide, peracetic acid and perbenzoic acid-sometimesactivated by water-soluble reducing agents such as a ferrous compound,sodium bisulfite or hydroxylamine hydrochloride-and other free radicalproducing materials such as 2,2'-azobisisobutyronitrile.

Emulsifiers, although not required for the invention, are oftenadvantageously included in the aqueous dispersion for stabilization ofthe dispersion and/or to provide particle size control. Usually at leastone anionic emulsifier is included and one or more of the knownnon-ionic emulsifiers may also be present. Representative types ofanionic emulsifiers are the alkyl aryl sulfonates, the alkali metalalkyl sulfates, the sulfonated alkyl esters, the fatty acid soaps andthe like. Specific examples of these well known emulsifiers, for thepurpose of illustration and not for limitation, are dodecylbenzenesodium sulfonate, sodium butyl naphthalene sulfonate, sodium laurylsulfate, di-sodium dodecyldiphenyl ether disulfonate, n-octadecyldisodium sulfosuccinate and dioctyl sodium sulfosuccinate. Other speciesof useful anionic emulsifying agents will be known. Typical non-ionicemulsifiers (surfactants) are compounds formed by the reaction of analkylene oxide, such as ethylene oxide, propylene oxide, or butyleneoxide with long chain fatty alcohols, long chain fatty acids, alkylatedphenols, and long chain alkyl mercaptans; the alkylene oxides beingreacted in a ratio such as moles to 20 moles or higher such as up to 50moles per mole of the coreactant. Similarly effective compounds aremonoesters such as the reaction products of a polyethylene glycol withlong chain fatty acids, for example, glycerol monostearate, sorbitantrioleate, and partial and complete esters of long chain carboxylicacids with polyglycol ethers of polyhydric alcohols. By long chain inthe above de scription usually is meant an aliphatic group having fromsix carbon atoms to 20 or more. Combinations of two or more emulsifyingagents from one or more of the classes may be employed if desired forspecial effects.

The amount of emulsifier during polymerization usually is from about0.05 part to about 5 parts preferably from about 0.5 part to about 3parts, for each 100 parts of monomers on a weight basis.

Sometimes part or all of these surfactants are introduced into thepolymerization mixtures as a component of a preformed seed latex. Insuch a process, to small amounts of a seed latex are added water,constituent monomers, the free-radical producing catalysts and any otheringredients of the emulsion polymerization recipe in an incremental or acontinuous manner while maintaining agitation of the contents of thepolymerization zone under conditions "of pressure suitable for themonomeric composition being used and at a temperature suitable for theparticular catalyst system being used, such temperatures usually beingbetween about 0 C. and 115 C.

Conventional additives for latex compositions may be included in smallbut usual amounts and in a known manner. Such materials include, but arenot restricted to,

chain transfer agents, short stopping agents, bufifers, antifoamingagents, chelating agents, inorganic salts, additional surfactants,plasticizers, tinting materials, bactericides, or other preservativesand the like.

The aqueous dispersions, i.e., the latex compositions, usually areprepared at a solids content of from about 30 percent to about 70percent, preferably from about 40 percent to about percent by weight.

The additive method also encompasses embodiments in which thecarbocyclic compound is added to other constituents of the compositionbefore or during emulsion polymerization of the monomers to form thelatex.

The amount of the carbocyclic compound which is effective to providewater-redispersibility usually is from about 1 part to about 10 parts,preferably from about 2 parts to about 8 parts, for each 100 parts ofcopolymer in the latex. Ordinarily the minimum proportion of carbocycliccompound would not be used with a latex containing'the minimum amount ofcopolymerized carboxylcontaining monomer or with a latex having anaverage particle size near the smaller end of the particle-size range.The carbocyclic compound can be added either as the acid or as awater-soluble salt of the acid. However, when the pH of the latex isadjusted above 7 as described below,

the carbocyclic compound will be, at least partially, in thewater-soluble salt form.

The alternate in situ method of preparing compositions of this inventioncomprises the emulsion polymerization of the same kinds of monomers asnoted above except that the aliphatic conjugated diene which is optionalin the preparation of the pre-formed latex is a requirement in the insitu method and there is also required fumaric acid or a water-solublemonoalkyl ester of an ethylenically unsaturated dicarboxylic acid havingfrom 4 to 5 carbon atoms. The monoalkyl esters are represented by themonomethyl, monoethyl and monopropyl esters of maleic acid, fumaricacid, itaconic acid and citraconic acid but the monomethyl esters arepreferred and the especially preferred ester is monomethyl maleate. Theamounts of the various components of the monomeric composition are fromabout 20 percent to about 97.5 percent, preferably from about 30 percentto about 60 percent, of the aliphatic conjugated diene, from about 2.5percent to about 13 percent, preferably from about 4 percent to about 8percent, of fumaric acid or of the monoalkyl ester, from 0 to about 77.5percent, preferably from about 32 percent to about 66 percent, of anon-ionic monoethylenically unsaturated monomer and from 0 to about 8percent of another cap-ethylenically unsaturated carboxylic acid,provided that the total amount of ethylenically unsaturatedcarboxyl-containing monomer is not greater than about 13 percent. Theminimum amount of monoalkyl ester or fumaric acid ordinarily would beused only with the monomethyl esters, when another c p-ethylenicallyunsaturated carboxylic acid is also used or when polymerizationconditions are chosen such that a large particle-sized latex isproduced. Similarly, when the monethyl, and especially the monopropyl,esters are used, the amount should be selected from the upper part ofthe range.

In the in situ method the prescribed monomers are polymerized underconventional emulsion polymerization conditions at acid pH andoptionally with conventional added materials as summarized above.However, best results are obtained when the polymerization is carriedout in a sequential manner such that the fumaric acid or alkyl monoesteris present in the initial composition before p0- lymerization conditionsare generated, together with not more than about percent of the aqueousphase and optionally with a small amount of seed latex, then the othermonomeric constituents and the remainder of the aqueous phase togetherwith the catalyst are added as separate streams either incrementally orcontinuously until all of the constituents have been added.

During the emulsion polymerization process, some of the monoalkyl esteris copolymerized with the other monomeric constituents and some of itsreacts with the conjugated diene and hydrolysis occurs to form atetrahydrophthalic acid. Thus, there is obtained a latex of acarboxylcontaining polymer in admixture with a six-membered carbocycliccompound having two vicinal carboxyl substituents. It appears that whena half ester of itaconic acid is used, a rearrangement occurs such thatsome of the same kind of product is obtained, i.e., a carbocycliccompound having carboxyl groups attached directly to adjacentring-carbon atoms.

While the latex products of this invention may be used for a widevariety of purposes, they are particularly desirable for use in thepreparation of non-woven products and for use in coatings.

The latex products may be converted to dry compositions (which areredispersible in water to reform latex products having about the sameparticle size as the original latex) in several ways. For example, thelatex composition may be cast on a suitable surface such as glass andallowed to dry at ambient temperature or at higher temperatures but lessthan C., preferably not exceeding 60 C. Powdery products can be obtainedby spray-drying or freeze-drying techniques. However, for goodredispersibility the latex composition should have a pH value from about7 to about 14, preferably from about 8 to about 12. If the pH of thecomposition is lower than about 7, sufficient water-soluble base shouldbe added, before drying, to raise the pH to the desired value. Any ofthe water-soluble organic or inorganic base-acting compounds may be usedsuch as the lower molecular weight amines, for example, methyl amine,ethyl amine, n-propyl amine, n-butyl amine, n-amyl amine and2-aminoethanol; and the ammonium or alkali metal hydroxides such asammonium hydroxide, lithium hydroxide, sodium hydroxide and potassiumhydroxide. To assure continued redispersibility the dried productsshould not be heated above about 95 C.

Specific end-use products may be prepared by processes which start withthe products of the invention in the latex form as prepared; forexample, as binders in the manufacture of non-woven products. Providedsuch dry'products of the invention in the dry state such as an additivesimplified because of the redisperible nature of the binder. Otherend-use materials may be prepared using the products of the invention inthe dry state such as an additive to patching plaster, or to tape jointfiller. In addition, the latex products may be converted to the dry formfor sub- Throughout the specification and claims, all parts andpercentages are by weight unless otherwise indicated. The particle sizesare measured by light scattering with the Brice-Phoenix Photometer.

Examples l-14 The data for Examples 1-9 are summarized below in Table Iand for Examples 10-14 in Table II. The starting latex, having apolymeric composition as identified for each sample, has a polymersolids content between percent and percent and contains a small amountof an anionic or non-ionic surfactant. The latex of Example 14 andcomparative latex 14c contain a nonionie surfactant, nonyl phenolpolyethylene glycol. The other latexes contain small amounts of anionicsurfactants of various types such as sodium lauryl sulfate and thedisodium salt of dodecyldiphenyl ether disulfonic' acid. For eachexample, the latex is stirred, the carbocyclic compound is added asan'aqueous alkaline solution and stirring is continued for about 5minutes. The resulting compositions are tested for redispersibilityaccording to the test described above and the redispersibility type andparticle size are as listed in Tables I and II.

TABLE I Latex description Redispersed Copolymerized Mixture polymernon-ionic Carbocyclic monomers Acidic monomer compound Particle ParticleExample size, angsize, angnumbcr B Kind Amt. pH Kind Parts pH stromsType stroms 57 40 1A...- 3 8.1 NaTHR... 4 8.9 58 40 FA...- 2 7.0 Na'IHP.... 4 11.0 62 36 A 2 8.0 NaIHP-- 4 11.0 63 36 1A..-- 1 7.0 NaTHP 411.0 40 None 8.0 P 4 11.5 61 37 FA 2 7.0 3 11.0 58 39 3 8.6 5 10.0 57 401A...- 3 8.0 3 8.0 57 40 3 8.0 3 8.0 57 40 1A..-- 3 8.0 Ne4-MeP.-. 3 8.0

= See the list of abbreviations after Table III. Not examples of theinvention.

TABLEII v Latex description Redjspersed Mixture 1 Acidic Oarbocyclio Dome! E Copolymerlzed non-ionic monomers monomer compound x. No VeClg MAVAc VON EA VCl Kind Amt. pH Kind Parts pH 10. 78 18 AA.-- 4 5.0 Li THP11 4 3.6 Li 'IHP 12 7 4 5.0 Li THP. 13 I 78 4 6.0 NaTHP 1 4 7.5 LiTE 144 10.0 None B See the list of abbreviations after TABLE III. Notexamples of the invention.

sequent shipping and storage, with eventual use either in that form orcombined with water as a reconstituted latex. 5

A simple test for redispersibility is described as follows: A wet film,about 15 mils in thickness, is cast on a glass plate and allowed to dryto a clear, continuous film. The dry film on the glass plate is heldunder a deionized water tap which is turned on only enough to give asmall continuous stream of water. The degree of dispersibility is thenrated as: Type I, spontaneously redisperses to a latex having a particlesize about the same as the original latex even when the dry film hasbeen aged for more than one day; Type II, spontaneously disperses inwater to give a particle size somewhat larger than the original latexwhen the dry film has aged for up to about one day but requires lightrubbing thereafter; and Type III, redisperses in water only with lightrubbing to give a particle size considerably larger than the originallatex. A latex which does not show sufficient redispersibility to meetat least the requirements of Type III is classified as none.

The following examples are given to illustrate more clearly theprinciple and practice of this invention to those skilled in the art andare not for purposes of limitation.

In a comparative experiment, when 3 parts of a carbocyclic compoundwhich is insoluble in aqueous alkaline media, i.e., tetraphenylphthalicacid, is substituted for the sodium tetrahydrophthalate of Example 1, itis found that the product obtained is not redispersible.

Examples 15-25 In these examples (except as noted in Table III), into astirred, 3-liter glass pressure reactor are placed 55 parts of deionizedwater, 0.02 part of the trisodium salt of N-hydroxyethylene-diamine-triacetic acid, 0.10 part of the sodium salt ofdodecyldiphenyl ether disulfonic acid, the

. amount indicated in Table III of the specified monoalkylethylene-diamine triacetic acid, 0.5 part of the sodium salt ofdodecyldiphenyl ether disulfonic acid, 0.2 part of sodium hydroxide and0.5 part of sodium persulfate in 45 parts of deionized water is added ina continuous manner over a period of 4% hours. Starting at the same timeas the first aqueous continuous stream there is added in a continuousmanner over a period of 4 hours a monomer stream containing the monomersas listed in Table 'III and 1 part of bromoform. The reaction mixture isstirred for an additional three hours at 90 C. after the last of thecomponents are added. Stable latex products are obtained thereby havingan acid pH and the particle sizes indicated in Table III. To portions ofthe latex products is added suflicient sodium hydroxide to raise the pHto about 8 and the redispersibility according to the test describedabove is found to be as indicated in Table III.

Sodium hydroxide is added to other portions of the latex productaccording to Example 19 to raise the pH above 8. Such material from oneportion is spray dried to obtain a dry powder and another portion isfreeze dried. An equivalent amount of water is added to the driedmaterial with moderate stirring to obtain latexcs having 50 percentsolids. The particle size for each reconstituted latex is found to beabout 2200 Angstroms.

The presence of 1,2,3,6-terthydrophthalic acid in Examples 15-25 isconfirmed by nuclear magnetic resonance. In this analysis, a portion ofthe latex is diluted with water to 20 percent solids. The diluted latexis centrifuged and the, serum obtained therefrom is filtered through aMillipore filter, Model XX 424700, membrane No. PSWP 04710, (MilliporeCorporation, Bedford, Mass.) to remove materials having a molecularweight greater than about 1000. A l-milliliter portion of the filtratethus obtained is dried under flowing nitrogen atroom temperature and thedried residue is redissolved in 1 milliliter of deuterium oxide whichcontains 3 percent of an internal chemical shift reference (sodium 3-trimethylsilylpropionate-2,2,3,3-d4) and the nuclear magnetic resonancespectra at 60 megahertz and 260 megahertz is recorded. A small amount ofa compound known to be l,2,3,6-tetrahydrophthalic acid is added, thenuclear magnetic resonance spectra is again recorded and super positionof the pertinent absorption peaks is seen at a higher amplitude but nonew distinct absorption peaks are 10 VCN=Acrylonitrile IA=Itaconic acidFA=Fumaric acid AA=Acrylic acid Na HP=Disodium salt ofl,2,3,6-tetrahydrophthalic act Na o-P=Disodium salt of o-phthalic acidNa TClP=Disodium salt of tetrachloro-o-phthalic acid Na TBrP-=Disodiumsalt of tetrabromo-o-phthalic acid Na 4-MeP=Disodium salt of4-methyl-o-phthalic acid Na HHP=Disodium salt of hexahydrophthalic acidLi THP =Dilithium salt of l,2,3,6-tetrahydrophthalic acid MMM=Monomethylmaleate (methyl acid maleate) MEM=Monoethyl maleate MPM=Monopropylmaleate MBM=Monobutyl maleate MMI=Monomethyl itaconate EXAMPLE 26 Alatex is prepared as described in Examples 15-25 except that, instead ofthe alkyl monoester, there is used 3 parts of 1,2,3,6-tetrahydrophthalicacid and the monomeric constituents are 49 parts of styrene, parts ofbutadiene and 3 parts of itaconic acid. The product is an acidic latexhaving a particle size of 1900 Angstroms. In the redisp'ersibility test,the latex product'is found to be redispersible, Type I, and the particlesize of the reconstituted latex is 1900 Angstroms.

In a comparative test, a similar latex prepared in the same manner butwithout the tetrahydrophthalic acid, i.e., prepared from 52 parts ofstyrene, 45 parts of butadiene and 3 parts of itaconic acid, is foundnot to be redispersible. In another comparative test, a similar latexprepared in the same manner but without the itaconic acid, i.e.,prepared from 52 parts of styrene, 45 parts of butadiene and 3 parts of1,2,3,6-tetrahydrophthalic acid, is also found not to be redispersible.

What is claimed is:

1. A film-forming latex composition having an average particle diameterof from about 500 Angstroms to about 10,000 Angstroms which when driedat a pH greater than about 7 is redispersible in water to form a latexhaving evident. 4.5 bstantlally the same particle diameter as theoriginal TABLE III Monomers polymerized Redlspersed material Product,

Other non-ionic Alkyl monoester particle Particle Ex. size, size, No. SB Kind Amt. Kind percent angstro Type angstroms Remarks 5 2,050 I 2,1004.0 2.100 2,150 12.5 2,600 2,650 5 2,360 2,950 5 2,160 I 2,250 M 5 2,480M 5 2,550

M 5 2,350 2,350 22 56 M 5 3,000 3,000 23 30 M 5 1,840 1,850

65 5 2,350 24-.--40 S MMM- 5 2,450 2,550 25...... 10 45 V6012- 40 MMM. 51,650 1,700 Polymerized at 70 1 Too large to measure with Brice-Phoenixinstrument. Not examples of the invention.

LIST OF ABBREVIATIONS FOR TABLES I, II AND III S=Styrene B==ButadieneVeCl =Vinylidene chloride MA=Methyl acrylate VAc=Vinyl acetate EA=Ethylacrylate VCl=Vinyl chloride ISP=Isoprene about C.

2. The latex of Claim 1 in which the a,p-e'thylenically unsaturatedcarboxylic acid comprises from about 3 percent to about 5 percent of thecopolymer.

3. The latex composition of Claim 1 in which the copolymer contains fromabout 20 percent to about 97.5 percent of a polymerized aliphaticconjugated diene.

4. The latex composition of Claim 3 in which the aliphatic conjugateddiene is butadiene.

5. The latex composition of Claim 3 in which the copolymer contains apolymerized alkenyl aromatic compound. I v

'6. The latex composition of'Claim 5 in which the alkenyl aromaticcompound is styrene.

7. The latex composition of" Claim 1 in which the copolymer containsfrom about 30 percent to about 60 percent of an aliphatic conjugateddiene.

8. The latex composition of Claim 1 in which the copolymer is present asparticles having an average diameter of from about 1500 Angstroms toabout 4000 Angstroms.

9; The latex composition of Claim 1 in which the polymerizable,essentially water-insoluble monomeric composition comprises an acrylicester.

-10. The latex composition-of Claim 1 in which the polymerizable,essentially water-insoluble monomeric composition comprises vinylidenechloride.

11. The latex composition of Claim 1 in which the polymerizable,essentially water-insoluble monomeric composition comprises vinylacetate.

12. The latex composition of Claim 1 in which the amount of carbocycliccompound is from about 2 parts to about 8 parts for each 100 parts ofcopolymer.

13. The latex composition of Claim 1 in which the carbocyclic compoundis a phthalic acid.

14. The latex composition of Claim 1 in which the carbocyclic compoundis a 1,2,3,6 tetrahydrophthalic acid.

15. The latex composition of Claim 1 in which the carbocyclic compoundis a hexahydrophthalic acid.

16. A dried film obtained from the latex composition of Claim 1.

17. A dried powder obtained from the latex composition of Claim 1.

18 A water-insoluble polymeric composition which in the dry state isdispersible in water to form a latex having a particle size of fromabout 500 Angstroms to about 10,000 Angstroms comprising a mixture of acopolymer of from about 1 percent to about 10 percent of ana,B-ethylenically unsaturated carboxylic acid and from about percent toabout 99 percent of an essentially water-insoluble, ethylenicallyunsaturated monomeric composition and a six-membered carbocycliccompound having vicinal carboxyl substituents in an amount sufficient toprovide water-dispersibility; said carbocyclic compound being soluble inaqueous alkaline media and said copolymer being film-forming attemperatures below about C.

19. The polymeric composition of Claim 18 which is in theform of a film.

20. The polymeric composition of Claim 18 which is I in the form of apowder.

References Cited UNITED STATES PATENTS 3,409,578 11/1968 Hiva 26029.63,232,899 2/1965 Guziak 26029.6 3,092,600 6/1963 Ozawa, et al. 26029.6

WILLIAM SHORT, Primary Examiner P. -F. KULKOSKI, Assistant Examiner US.Cl. X.R.

26029.7 H, 29.6 TA

mg?! STATES PATENT OFFICE CERTIFEATE CORRECTION Patent No. 3 I 822 rDated July 2, 1974 a a Inventor( Y Alfred lson It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 10, line 72, the hyphenated portion of a word "boxylic" should be-bocycli.c-.

Signed and sealed this 18th day of February 1975.

(SEAL) t a Attes n C. MARSHALL DANN RUTH Ca MASON Q Commissioner ofPatents Attesting Officer and Trademarks 1 UNITED STATES PATENT OFFICE aCERTIFICATE OF CORRECTION Patent No. 3,822,230 Da July 2, 1974lnventofls) Alfred R. Nelson It is certified that; error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

F I w Column 3, line 61, the worci "water-solu should be water-insol IColumn 6, line the word monethyl should be --monoethyl--.

Column 6, line 52', the word "its" should be --it---.

Column 7, line 18, delete the words "of the invention in the dry statesuch as an additive" and insert the words --are not'heated above 95C thedisposal problem is--.

Column 7, line 19, the word "redisperible" should be -redispers'ible-.

Column 9, line 25, the word "terthydrophthalic" should be-tertrahydrophthalic- Signed and sealed this 15th day of October 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

